Copper-silver-beryllium-manganese alloy



3, ages of silver can be employed and that very Patented Sept. 27, 1938 UNITED STATES PATE NT orrica COPPER- SILVER BERYLLIUM- MANGANE SE ALLOY I V Franz R. Hensel and Earl I. Larsen, Indianapolis,

4 Ind., assignors to P. R. Mallory & 00., Inc.,

Indianapolis, Ind., a corporation of Delaware No Drawing. Original application October 9.

1937, Serial No. Plication June 168,199. Divided and this ap- 9, 1938, Serial No. 212,685

' 5 Glaims. (01. 75-161) This invention relates to alloys, and more particularly to copper alloys of improved charactertics.

The present application is a division of copending-application S. N. 168,199, filed October 9, 1937.

An object of the invention is to produce an improved copper base alloy.

Another object is to improve copper-silverberyllium alloys.- 1

Other objects of the invention will be apparent from the following description taken in connection with the appended claims.

The present invention comprises the combi nation of elements, methods of manufacture, and the product thereof brought out and exemplified in the disclosure hereinafter set forth, the scopeent time have not found commercial use, be

cause of their high cost. In our researches, we have discovered that considerably lower percentexcellent properties are obtained with such alloys.

Copper-silver alloys are susceptible to age hardening. This age hardening, however, is manifested more in improvements in electrical conductivity than in improvements in hardness. The hardness of-alloys usually has to be obtained by cold working. Due to the fact that the cop-' per-silver system is inherently an age hardening system, the annealing point of such cold worked alloys is fairly high. Silver, furthermore, has the outstanding advantage that it ,will not decrease the electrical conductivity materially when alloyed with copper. This also is due to the very limited solid solubility of silver in copper.

We have found that at 600 degrees C., approximately 2.5% silver is held in solid solution, while at 200 degrees 0., only 0.3% of silver is held in solid solution, and at room temperature, this solubility is still less. This indicates definitely that show a conductivity oxidation characteristics.

with small percents'of silver, below 5% aenm... effects-can be obtained, as far as precipitation hardening is concerned. By combining the effects of age hardening of the copper-silver and the copper-beryllium system, an alloy can be produced which shows a very high hardness obtained with the copperberyllium system, and an improved electrical conductivity, such as is obtained in the coppersilver system.

It is possible, for instance, to produce an alloy containing 2 to 4% silver and 0.3 to 0.75% beryllium, which, after suitable heat treatment will sile strength of 95,000 p. s. i.

It is also possible to reduce the silver contents to very low limits and obtain an-improved alloy,

the improvement consisting not only in a higher of close to 50%, and a ten- 1 electrical conductivity and in a higher age hardening temperature, but also in superior characteristics, in regard to corrosion resistance and thermore suitable for electrical contacting purposes, because they retain a comparatively, low contact resistance. 1

We have found that the' 'addition of manganese to the copper, silver and beryllium produces a marked improvement. The alloys thus produced may preferably contain the ingredients in the following proportions:

Percent Bery 0.05 to 3 Silver 0.05 to 4 Manganese 0.05 to 10 Copper Balance Alloys of the type described may also contain in some instances up to several percent of silicon, tin, zirconium, titanium, magnesium, zinc, cadmium, aluminum, calcium and lithium.

Within these composition ranges, there are a number of specific alloys which have been found to be of Particular importance. Two of the alloys'are listed below:

Percent A. Beryllium .2 tol Silver .1 to 2.5 Manganese 0.05 to5 Copper Balance B. Beryllium 1 to 2.5 Silver 0.1 to 2.5 Manganese 0.05 to 5 Copper Balance The alloys can be made according to standard alloying methods, such as melting the copper and The alloys are fur- .at elevated temperatures.

adding thei desired amounts of silver and manganese. Afterwards the correct amount of beryl lium may be introduced in the form of a copperberyllium master alley or any other form and the'material can be cast either in a chill mould or in a sand mould, at the correct temperature.

After the alloy has been prepared according to standard alloy ng methods, the heat treatment may be carried out as follows- I The alloy in the form ofa billet or a sand casting or any desired form. is raised in temperature to above 700 degrees C. and its melting point. The alloy is then quenched from this temperature and subsequently aged at temperatures ator below 600 degrees .C. This heat treatment results in considerable improvementsin the physcal properties ofthe alloy. The alloy is particularly suitable for applications where high hard ness and high electrical conductivity are required,

and where physical properties have to be retained further very extensive'use in applications where thematerial is used for electrical contacting purposes, such as contactor contacts where arcs are drawn and surface oxidation produces high resistance films on ordinary copper alloys.

The alloys are furthermore very suitable for springs, particularly springs which' have to carry current or which have to withstand certain tema perature rises without losing their elastic prop- I erties.

The alloys have further found considerable use for wear resistance purposes and applications, such as pressure welding electrodes and resistance welding dies in general. 1

The materialis also suitable for special applications where springs of intricate design must be formed in the soft condition; that is after quenching, and where a high hardness can be reached after a suitable age hardening treat ment. I

The alloys have found- The alloys can be manufactured in the: form of extruded bars. or sheets or flne'wire. Zl'he alloys have also particular merit if used in the;

' ried out in specific embodiments thereof, it is not desired to be limited thereby. butit is in-' tended to cover the invention broadly within the spirit and scope of the appended claims. I

What is claimed is:

1 20/ 1. An alloy containing about0.05' to 3% beryllium, 0.05 1 .04% silver, 0. to 10% manganese "and the balan'cecopper.

2. image-hardened alloycontaining about 0.05

t 3% beryllium, 0.05 to 4% silver, 0.05 to manganese, balance substantially all copper,

3. Analloy containing about 0.2 to 1% beryland the balance copper.

'4. An alloy containing about 1 to 2.5% beryl- 1mm. 0.1zt0 2.5% silver, 0.05 to 5% manganese and the balance copper.

lium, 0.1 to 2.5% silver, 0.05 to 5% manganese 5. An electric contacting element of the type comprising pressure-exerting welding electrodes 1 and the like formed of an alloy containing about 0.05 to 3%beryliium, 0.05 to 4% silver, 0.05 to 10% manganese and the balance copper.

FRANZ R. HENSEL. EARL I. LARSEN. 

